Test #3 – Microbiology – Flashcards
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| Purple Nonsulfur Bacteria |
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| can produce cellular cysts resting cells resistant to desiccation but less tolerant of heat and UV than bacterial endospores made in response to nutrient limitation have thick outer coat and store polyhydroxybutyrate with one exception (genus Rhodocyclus) all are a-proteobacteria metabolically flexible normally grow anaerobically as anoxygenic photoorganoheterotrophs possess bacteriochlorophylls a or b in photosystems located in membranes that are continuous with plasma membrane some can oxidize sulfide, but not elemental sulfur, to sulfate in absence of light most grow aerobically as chemoorganoheterotrophs some carry out fermentation, photoheterotrophy, photoautotrophy, and grow anaerobically Rhodosprillum best studied metabolic diversity |
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| Phylum Proteobacteria |
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| the largest phylogenetically coherent bacterial group with more than 500 genera remarkable diverse morphologically, physiologically, and other ways volume 2 of Bergey’s Manual (2nd edition) is devoted to this group of bacteria |
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| Class Alphaproteobacteria |
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| seven orders, 20 families Rickettsiales may have been the earliest ?-proteobacteria most of the oligotrophic bacteria most abundant bacteria in oceans evolved to live within plants and animals resulting in genome reduction or expansion metabolically diverse methylotrophy, chemolithotrophs, nitrogen fixers |
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| Genus Rhodospirillum |
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| produces H2 novel biodegradable plastic In Alphaproteobacteria oxidize carbon monoxide to carbon dioxide morphologically diverse most motile by polar flagella found in mud and water of lakes and ponds with abundant organic matter and low sulfide levels; some marine species |
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| genus Rickettsia |
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| order Rickettsiales; family Rickettsiaceae In Alphaproteobacteria very small, gram-negative, non-flagellated, diverse morphology all species are parasitic or mutualistic grows in vertebrate erythrocytes, macrophages, vascular endothelial cells live in blood sucking arthropods – vectors or primary hosts genome sequence similar to mitochondria arose from endosymbiotic association free living, aerobic bacterium became intracellular parasite of proto-eukaryotic cell that lacked organelles gene reduction occurred and loss of free living ability lack glycolytic pathway do not use glucose as energy source oxidize glutamate and TCA cycle intermediates (e.g., succinate) take up and use ATP and other materials from host cell reproduction enters host by phagocytosis escapes phagosome reproduces in cytoplasm host cell bursts |
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| Rickettsia prowazekii and Rickettsia typhi |
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| typhus fever |
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| Rickettsia rickettsii |
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| Rocky Mountain Spotted Fever |
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| Genus Rhizobium |
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| gram-negative, pleomorphic, motile rods often contain poly-b-hydroxybutyrate granules grow symbiotically as nitrogen-fixing bacteroids within root nodule cells of legumes most successful plant family on earth In Alphaproteobacteria |
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| Genus Agrobacterium |
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| do not stimulate nodule formation or fix nitrogen invade crown, roots, and stems of many plants transform infected plant cells into autonomously proliferating tumors e.g., Agrobacterium tumefaciens causes crown gall disease by means of tumor-inducing (Ti) plasmid In Alphaproteobacteria |
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| Genus Brucella |
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| important human and animal pathogen undulant fever – zoonosis tiny, faintly staining coccobacilli In Alphaproteobacteria |
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| Nitrifying Bacteria |
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| very diverse chemolithoautotrophs nitrification – gain electrons from oxidation of ammonium to nitrate or nitrite nitrite further oxidized to nitrate ammonia ? nitrite ? nitrate conversion of ammonia to nitrate by action of two genera e.g., Nitrosomonas – ammonia to nitrite e.g., Nitrobacter – nitrite to nitrate fate of nitrate easily used by plants lost from soil through leaching or denitrification divided into several taxa class Alphaproteobacteria e.g., genus Nitrobacter class Betaproteobacteria e.g., genera Nitrosomonas and Nitrosospira class Gammaproteobacteria family Ectothiorhodospiraceae e.g., genus Nitrococcus family Chromatiaceae e.g., genus Nitrosococcus In Alphaproteobacteria |
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| Class Betaproteobacteria |
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| seven orders, 12 families considerable metabolic diversity overlap ?-proteobacteria metabolically but generally use decomposed organic matter anoxically some use hydrogen, methane, ammonia, volatile fatty acids |
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| Order Neisseriales |
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| one family, Neisseriaceae and 15 genera Genus Neisseria In Betaproteobacteria |
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| Genus Neisseria |
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| nonmotile, gram-negative cocci most often occur in pairs with adjacent sides flattened may have capsules and fimbriae aerobic chemoorganotrophs oxidase positive and usually catalase positive may have capsules and fimbriae inhabitants of mucous membranes of mammals some human pathogens Neisseria gonorrhoeae – gonorrhea Neisseria meningitidis – meningitis In Betaproteobacteria |
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| Genus Bordetella |
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| gram-negative coccobacilli some have capsules aerobic chemoorganotrophs respiratory metabolism require organic sulfur and amino acids for growth mammalian parasites that multiply in respiratory epithelial cells nonmotile, encapsulated species whooping cough and kennel cough In Betaproteobacteria |
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| Order Nitrosomonadales |
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| number of chemolithotrophs e.g., two genera of nitrifying bacteria Nitrosomonas and Nitrosospira oxidize ammonia to nitrite enzyme ammonia monooxygenase (AMO) enzyme hydroxylamine oxidoreductase also auxotrophic metabolism fixes CO2 in Calvin cycle In Betaprotebacteria |
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| Genus Thiobacillus |
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| found in soil and aquatic habitats production of sulfuric acid can cause corrosion of concrete and metal structures may increase soil fertility by releasing sulfate used in leaching metals from low grade metal ores In Betaproteobacteria |
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| Class Gammaproteobacteria |
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| largest subgroup of proteobacteria contains 14 orders and 28 families very diverse physiological types chemoorganotrophs, photolithotrophs, chemolithotrophs, methylotrophs aerobic and anaerobic many deeply branching groups |
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| The Purple Sulfur Bacteria |
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| placed in order Chromatiales divided into two families, Chromatiaceae and Ectothiorhodospiraceae Family Ectothiorhodospiraceae contains eight genera In Gammaproteobacteria |
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| Order Legionellaceae |
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| family Legionellacaea genus Legionella family Coxiellaceae genera Coxiella and Rickettsiella all are intracellular pathogens dimorphic lifestyle (two forms) In Gammaproteobacteria |
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| Genus Legionella |
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| L. pneumophilia intensely studied causative agent Legionnaire’s disease transmission through aerosols intracellular pathogen of protozoa invade cooling towers, air conditioning, hot tubs gram-negative rods that replicates by binary fission Life cycle in Protist replicative forms (RFs) reside in host vacuole (replicative endosome) RFs differentiate into mature intracellular forms (MIFs) which are the infectious form MIF are metabolically dormant, heat tolerant, and resistant to antibiotics Hsp60 is invasin used to invade host cell In Gammaproteobacteria |
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| Genus Coxiella |
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| host range birds, insects, fish, rodents, sheep, goats, humans transmitted through aerosol life cycle similar to L. pneumophilia small cell variant (SCV) enters cell by phagocytosis phagosome low pH triggers SCV to become metabolically active SCV differentiates into large cell variant (LCV) replicates by binary fission, are infectious long-term survival outside the host In Gammaproteobacteria |
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| Order Pseudomonadales |
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| contains family Pseudomonadaceae Pseudomonas is the most important genus in the order Pseudomonadales heterogenous - 60 species gram-negative straight or slightly curved rods 0.5 to 1.0 mm by 1.5 to 5.0 mm in length motile by one or several polar flagella lack prosthecae or sheaths chemoheterotrophs with respiratory metabolism usually use oxygen as electron acceptor sometimes use nitrate as electron acceptor have functional TCA cycle most hexoses are degraded by Entner-Duodoroff pathway degrade wide variety of organic molecules mineralization - microbial breakdown of organic materials to inorganic substrates important experimental subjects some are major animal and plant pathogens some cause spoilage of refrigerated food can grow at 4°C In Gammaproteobacteria |
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| Genus Azotobacter |
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| often pleomorphic, motile rods aerobic, catalase positive chemoorganotrophs widespread in soil and water In Gammaproteobacteria |
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| Order Vibrionales |
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| contains one family, Vibrionaceae; eight genera most are aquatic, most free-living straight or curved rods, oxidase positive, flagellated some important pathogens some symbiotic in luminous organs of fish closely related to two other orders Enterobacteriales and Pasteurellales In Gammaproteobacteria |
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| Vibrio Cholerae |
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| pathogen that causes cholera genome has been sequenced has two circular chromosomes copies of some genes present on both chromosomes cholera toxin gene is integrated phage on chromosome 1 In Gammaproteobacteria |
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| Order Enterobacteriales |
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| one family, Enterobacteriaceae; 44 genera enteric bacteria or enterobacteria facultative anaerobes chemoorganotrophs that degrade sugars by glycolytic pathway can cleave pyruvate to yield formic acid (formic acid fermentation) In Gammaproteobacteria |
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| Family Enterobacteriaceae |
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| two groups based on fermentation products majority are mixed acid fermenters produce lactate, acetate, succinate, formate, and ethanol others are butanediol fermenters butanediol, ethanol, and carbon dioxide biochemical tests used to distinguish genera in addition to morphology, motility, growth responses very common, widespread, and important In Gammaproteobacteria |
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| Escherichia coli |
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| probably best studied bacterium inhabitant of intestinal tracts of many animals used as indicator organisms for testing water for fecal contamination some strains are pathogenic gastroenteritis urinary tract infections In Gammaproteobacteria |
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| Salmonella |
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| typhoid fever and gastroenteritis In Gammaproteobacteria |
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| Shigella |
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| bacillary dysentery In Gammaproteobacteria |
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| Klebsiella |
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| pneumonia In Gammaproteobacteria |
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| Yersinia |
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| plague In Gammaproteobacteria |
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| Erwinia |
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| blights, wilts, etc., of crop plants In Gammaproteobacteria |
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| Order Pasteurellales |
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| one family, Pasteurellaceae; six genera small, nonmotile, oxidase positive important pathogens Pasteurella multiocida – fowl cholera Pasteurella haemolytica – pneumonia in cattle, sheep, and goats Haemophilus influenzae – variety of diseases, including meningitis in children; vaccine available In Gammaproteobacteria |
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| Class Deltaproteobacteria |
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| contains eight orders and 20 families divided into two general groups aerobic, chemoorganotrophic predators anaerobic, chemoorganotrophic sulfur- and sulfate-reducers |
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| Class Epsilonproteobacteria |
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| smallest of proteobacterial classes probably two one orders, Campylobacteriales and Nautiliales; three families slender gram-negative rods |
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| Campylobacter fetus |
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| reproductive disease and abortions in cattle and sheep Guillain-Barre syndrome triggered in molecular mimicry septicemia and enteritis in humans septicemia – pathogens or their toxins in blood enteritis – inflammation of intestinal tract In Epsilonproteobacteria |
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| Campylobacter jejuni |
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| abortions in sheep enteritis diarrhea in humans In Epsilonproteobacteria |
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| Genus Helicobacter |
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| at least 23 species isolated from stomachs and upper intestines of mammals e.g., Helicobacter pylori causes gastritis and peptic ulcer disease motility important for colonization does not grow below pH 4.5 urease converts urea to ammonia and CO2 urea hydrolysis appears to be associated with virulence In Epsilonproteobacteria |
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| Epsilonproteobacteria |
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| newly discovered are thermophilic, chemolithoautotrophic, and others found in marine hydrothermal vents, terrestrial springs, ground water, oil-field brines, limestone caves, sulphidic springs found in filamentous microbial mats in anoxic, sulfide-rich cave springs |
